Spark-plug



G. T. DUCHTEHMANN.

SPARK PLUG.

Arrucnrlon man 1AN.29. |919..

rammed June 1,1920.

Inventor: Geor'ye Tachermann nection with the other UNITED STATES PATENT OFFICE.

eEoEGE r. nocnrnnmamr. oF Passaic, NEW JERSEY.

SPARK-PLUG'.

Specification of Letters Patent.

Patented June 1, 1920.

Application led January 29, 1919. Serial No. 278,756.

To all whontzt may concer/n.'

Be it known that I, GEORGE T. DOCHTER- -MANN, a citizen of the United States and a plug which are normally exposed to carbon and oil deposit are protected against access of carbon and oil. provide improved priming means in conimprovements. Other features will appear later herein.

A further object is to My improvements comprise features illus\ trated in their preferred embodiment in the vdrawing accompanying this specification wherein the figure is a vertical section of a spark plug embodying my improvements.

The. usual tubular body 2, of some approved design is provided with the usual threaded end 3 for mounting theplug in place for use. The bore 4 of body 2 is enlarged at its upper end 5 vto provlde seat 6 for shoulder 7 of tubular insulating member 8. Said insulating member 8 may'be held in place in body 2 by means of the usual hollow nut 9. passage 10 of insulator 8 is supported tubular conductor 11. The upper end of said conductor is provided with an outer threaded portion 12 onto which is screwed nut 13 for holding said conductor in place withits all around, beyond the bore 4 ofbody 2 and 1n close proximity to the lower end 21 thereof, thus forming a spark gap and at the vsame time providing an efiicient obstruction to the entrance of carboncharged gas and oil to the space within the lower part of bodyA 2. By this means long life andeilicient service is assured the lug. Furthermore the peculiar formo my improved priming cup provides a tight seal for the top of tube 11 and said cup may be readily removed for cleaning both ity and the chan-V nel in said tube. .Also the absence of springs, balls, and other loose pieces commonly used in priming cup caps eliminates'the possibility of their loss when taking the cup off for cleaning.

I claim:

1. In a device of the class described, a tube, and a priming cup adj ustably mounted on one endportion thereof, said cup having a rigid member arranged to close the adjacentend of said tube when said cup is ad- Within lengthwise shoulder 14 against the lower end of-insu-A lating member 8. Between nuts 13 and 22, the connecting wire may be secured. On the top of said conductor 11 is screwed priming cup' 15. Said cup is provided with dished upper wall 16 from which oneor more pas: sages 17'lead to annular channel 18, the upper wall 19 of which forms a valve seat or closing member for the upper end of conductor tube 11, when screwed down thereagainst. On the lower end of tube 11 is secured flange V20, which projects outwardly justed in one direction and having a passage in communication with the interior of said tube when said cupis adjusted in another direction.

2. In combinationwith a tube, a priming cup threaded on one end portionI of said .tube and having a rigid member arranged to close the adjacent end of said tube when the cup is threaded. onto the tube, said cup being provided with a passage in communicationwith the interior of `said tube when said cup is threaded partially off of said tube.

3. A'device of 'the class described including a tube, a priming cup threaded on one end portion of said tube and having a dished upper face, a member rigid with said priming cup arranged to close the adjacent end of said tube when said cup is secured down against said end, said cup having an annular channel therein below said tube closing member and having a passage from said dished face to said annular channel.

In witness whereof, I hereby affix my signature this 28 da of J anuzil'y 1919.

GEORG T. Doc rERMANN. 

